Comparing Frequency Transfer via GNSS and Fiber in a Common-clock Configuration

authored by: Ahmed Elmaghraby, Thomas Krawinkel, Steffen Schön, Ann Kathrin Kniggendorf, Alexander Kuhl, Shambo Mukherjee, Jochen Kronjäger, Dirk Piester
Abstract: Realizing a clock-based geodetic network with a relative uncertainty level of 10^-18 has been a significant objective for the scientific community. This network can be utilized for realizing more accurate geodetic reference frames and for testing the fundamental laws of physics, such as the theory of relativity. Typically, optical fibers are connecting optical clocks in such a network. For the last decades, Global Navigation Satellite Systems (GNSSs) have built a trustful and easy-setup method for frequency and time transfer. However, recently optical fiber link networks showed better frequency instability. In this study, we investigate the limits of GNSS-based frequency transfer links with the help of an optical fiber link as ground truth. Therefore, we analyze the GNSS data acquired in a dedicated common-clock experiment over a 52 km baseline. We focus on developing two algorithms to estimate the receiver clock differences, hence the frequency instability. These are the single difference (SD) approach with ambiguity fixing as a common view technique, and precise point positioning as an all in-view technique. We discuss the frequency instability achieved by the optical fiber link as well. We evaluate further the performance by computing the modified Allan deviation for both cases. The results show that the ambiguity-fixed solution of SD-CV improves the relative frequency instability via GNSS to reach the order of 3-5 · 10^-17 at one day averaging time. In the optical fiber link, which is the basis of the common clock setup, the round-trip instability shows better performance for all averaging times.
Organisation(s): Institute of Geodesy
External Organisation(s): Physikalisch-Technische Bundesanstalt PTB
Type: Conference contribution
Pages: 105-116
No. of pages: 12
Publication date: 2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Computer Science Applications, Control and Systems Engineering, Electrical and Electronic Engineering, Mechanical Engineering
Electronic version(s): https://doi.org/10.15488/17444 (Access: Open)
https://doi.org/10.33012/2024.19592 (Access: Closed)

BibTeX

@inproceedings{a901f4a544414616baae22259499fe14,
title = "Comparing Frequency Transfer via GNSS and Fiber in a Common-clock Configuration",
abstract = "Realizing a clock-based geodetic network with a relative uncertainty level of 10-18 has been a significant objective for the scientific community. This network can be utilized for realizing more accurate geodetic reference frames and for testing the fundamental laws of physics, such as the theory of relativity. Typically, optical fibers are connecting optical clocks in such a network. For the last decades, Global Navigation Satellite Systems (GNSSs) have built a trustful and easy-setup method for frequency and time transfer. However, recently optical fiber link networks showed better frequency instability. In this study, we investigate the limits of GNSS-based frequency transfer links with the help of an optical fiber link as ground truth. Therefore, we analyze the GNSS data acquired in a dedicated common-clock experiment over a 52 km baseline. We focus on developing two algorithms to estimate the receiver clock differences, hence the frequency instability. These are the single difference (SD) approach with ambiguity fixing as a common view technique, and precise point positioning as an all in-view technique. We discuss the frequency instability achieved by the optical fiber link as well. We evaluate further the performance by computing the modified Allan deviation for both cases. The results show that the ambiguity-fixed solution of SD-CV improves the relative frequency instability via GNSS to reach the order of 3-5 · 10-17 at one day averaging time. In the optical fiber link, which is the basis of the common clock setup, the round-trip instability shows better performance for all averaging times.",
author = "Ahmed Elmaghraby and Thomas Krawinkel and Steffen Sch{\"o}n and Kniggendorf, {Ann Kathrin} and Alexander Kuhl and Shambo Mukherjee and Jochen Kronj{\"a}ger and Dirk Piester",
note = "Publisher Copyright: {\textcopyright} 2024 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.; 55th Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2024 ; Conference date: 22-01-2024 Through 25-01-2024",
year = "2024",
doi = "10.15488/17444",
language = "English",
series = "Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
pages = "105--116",
booktitle = "55th Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2024",
address = "United States",
}